Brominated flame-retardants are known to be highly effective and in many cases are the only option for reducing the fire risk of synthetic materials such as rigid or flexible polyurethane foams. However, the growing concern regarding health and ecological issues has led inventors to develop a new reactive macro-molecular flame retardant.
Environmental and health problems diminish if a flame retardant is either reacted into the polymer matrix and cannot be leached-out, or if the flame retardant has a sufficiently high molecular weight that it does not volatize, and is not likely to bio-accumulate in living tissues.
Compounds containing a pentabromobenzyl moiety are known as flame retardants. Pentabromobenzyl acrylate (EP 481126), pentabromobenzyl terephthalate (DE 33 20 333), and pentabromobenzyl tetrabromophthalate (EP 47866) are reported to be used in flame retardant polymer compositions.
Low molecular weight pentabrombenzyl alkyl ethers containing one hydroxide group are described in US 2005/0124746. According to said publication, pentabromobenzyl alkyl ethers are prepared by the reaction of a pentabrombenzyl halide (PBBBr) with an aliphatic mono or di-alcohol (or the corresponding metal alcoholate), in the presence or absence of a base. Aliphatic diols (or the corresponding metal alcoholate) are reacted with a pentabrombenzyl halide, preferably PBBBr, to obtain the pentabrombenzyl ethers with one functional —OH group (Formula A).
Z=linear or branched —[(C2-C8)alkylene-O]n n represents an integer from 2 to 4k may be 0 or 1.